Secondary Logo

Journal Logo

Letters to the Editor: Letter to the Editor

In Response

Munday, Judy PhD; Osborne, Sonya PhD; Yates, Patsy PhD; Sturgess, David MBBS, PhD; Jones, Lee BSc; Gosden, Edward MSc

Author Information
doi: 10.1213/ANE.0000000000002892
  • Free

We appreciate the comments by Roth1 regarding our study2 and welcome the opportunity to discuss the issues raised. All women in our study received prophylactic phenylephrine infusion titrated to avoid hypotension, as per standard of care in our institution and as per the study protocol. However, in 4 cases, metaraminol was also administered with temperature decline in these cases ranging from 0.3°C to 1.5°C. Therefore, as we noted, due to individual differences in vasopressor use, only limited exploratory analysis of the secondary outcome of mean arterial pressure was conducted. While there is some limited evidence to suggest that patients receiving phenylephrine may experience higher end of procedure temperatures during orthopedic surgery under general anesthesia,3 more recent evidence from an observational study found that larger doses of phenylephrine resulted in lower (although not hypothermic) maternal temperatures.4 In our study in which all women received phenylephrine infusion, redistribution hypothermia remained clinically significant across both groups. With this conflicting evidence in mind, acknowledging that the physiology is complex and that there is no gold standard measure of vasodilation, it would be valuable for future studies among women receiving neuraxial anesthesia to accurately record the dose of vasopressors, as well as oxytocics, which may also influence maternal perception of heat because of flushing.

In response to the comments regarding the measurement of shivering in our study, we confirm that this was not assessed as a “surrogate” outcome for hypothermia. Although we did comment that the intensity and incidence of shivering may indicate the severity of hypothermia, our study also acknowledges that the cause of shivering may be multifactorial. Although we did not measure skin temperature in our study, we noted that thermal comfort did not influence shivering.

Judy Munday, PhD
School of Nursing, Faculty of Health
Queensland University of Technology
Brisbane, Queensland, Australia
[email protected]

Sonya Osborne, PhD
Australian Centre for Health Services Innovation
School of Public Health and Social Work/Faculty of Health
Queensland University of Technology
Brisbane, Queensland, Australia

Patsy Yates, PhD
School of Nursing, Faculty of Health
Queensland University of Technology
Brisbane, Queensland, Australia

David Sturgess, MBBS, PhD
Mater Research Institute, University of Queensland
Brisbane, Queensland, Australia

Lee Jones, BSc
Edward Gosden, MSc
Institute of Health and Biomedical Innovation
Queensland University of Technology
Brisbane, Queensland, Australia

REFERENCES

1. Roth JV. Hypothermia during cesarean delivery. Anesth Analg. 2018;126:2151–2152.
2. Munday J, Osborne S, Yates P, Sturgess D, Jones L, Gosden E. Preoperative warming versus no preoperative warming for maintenance of normothermia in women receiving intrathecal morphine for cesarean delivery: a single-blinded, randomized controlled trial. Anesth Analg. 2018;126:183–189.
3. Ro Y, Huh J, Min S, et al. Phenylephrine attenuates intra-operative hypothermia during spinal anaesthesia. J Int Med Res. 2009;37:1701–1708.
4. Hilton EJ, Wilson SH, Wolf BJ, et al. Effect of intraoperative phenylephrine infusion on redistribution hypothermia during cesarean delivery under spinal anesthesia. J Clin Anesth Manag. 2015;1.1:1–4.
Copyright © 2018 International Anesthesia Research Society